Postglacial paleoecology and effects of European settlement on the environment of Lake Hunger and Lake Lisgar, Southwestern Ontario /

dc.contributor.author

Winn, Ronald Frederick.

en_US

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2009-06-15T17:00:40Z

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2009-06-15T17:00:40Z

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1975-06-15T17:00:40Z

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http://hdl.handle.net/10464/1615

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This investigation has three purposes I to make a comparative
chemical study on sediment cores collected for Lake
Lisgar (man-made lake in an urban center) and Lake Hunger
(natural basin in a rural community) encompassing the time
since European settlement I to determine the postglacial chemical
history of Lake Hunger, and to determine the vegetational
history of the Lake Hunger area from postglacial time to the
present.
The minus 80 mesh fraction of 108 soil samples and 18
stream sediment samples collected in the vicinity of Lakes'
Lisgar and Hunger were analyzed for cold hydrochloric acid
soluble lead, zinc, nickel, cobalt, copper, aluminum, sodium,
potassium, calcium, magnesium, iron and manganese. Lacustrine
sediments from 5 boreholes in the Lake Lisgar basin were
collected. Boreholes 1, 2, 3, and 4 were analyzed for palynological
and chemical information and Borehole 5 was subjected
to pollen and ostracode analysis. Lacustrine sediments from
6 boreholes in the Lake Hunger basin were collected. Palyno-
-logical and chemical analysis were performed on Boreholes 1, 2,
3, 4, and 6 and Borehole 5 was analyzed for pollen. In addition,
radiocarbon dates were obtained on sediment samples from
Boreholes 4 and 5. A total of 8 surface samples were collected
from the margins of the Lake Hunger basin and these were
chemically analyzed in the laboratory. All of the lacustrine
sediments were ashed and analyzed for cold hydrochloric acid
soluble lead, zinc, nickel, cobalt, copper, aluminum, sodium,
potassium, calcium, magnesium, iron and manganese using a Perkin Elmer 40) Atomic Absorption spectrophotometer. The results
. obtained for the 12 elements were expressed as parts per million
in dry sediments.
It was found that man's influence on the element distribution
patterns in the sediments of Lake Lisgar appeared to be related
to his urbanizing developments within the lake vicinity,
whereas, the rural developments in the vicinity of lake Hunger
appeared to have had little effect on the element distribution
patterns in the lake sediments.
The distribution patterns of lead, zinc, nickel, cobalt,
aluminum, magnesium, sodium and potassium are similar to the
% ash curve throughout postglacial time indicating that the
rate of erosion in the drainage basin is the main factor which
controls the concentration of these elements in the sediments
of Lake Hunger.
The vegetational history, from palynological analysis, of
Lake Hunger from postglacial time to the present includes the
following stages: tundra, open spruce forest, closed boreal
forest, deciduous forest and the trend towards the re-establishment
of pine following the clearing of land and the subsequent
settlement of the Lake Hunger area by European settlers.
The concentrations of some elements (cobalt, nickel, iron,
manganese, calcium, magnesium, sodium and potassium) in the
sediments of Lake Hunger appears to be higher during pre-cultural
compared to post-cultural times. At least one complete postglacial
record of the chemical history within a lake basin is
necessary in order to accurately assess man's effects on his
environment.

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eng

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Brock University

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dc.subject

Paleoecology

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Glacial epoch

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dc.title

Postglacial paleoecology and effects of European settlement on the environment of Lake Hunger and Lake Lisgar, Southwestern Ontario /